This invention relates to a card edge connector having a plurality of metal terminals the tongue pieces of which are pushed against a plurality of elongated terminals which are formed on both sides of the connecting end portion of a printed circuit board, so that the terminals of the card edge connector are electrically connected to the terminals of the printed circuit board.
A card edge connector is engaged with a printed circuit lo board in such a manner that it holds an edge portion of the printed circuit board, namely, a connecting end portion. The connecting end portion is designed as follows: At a predetermined edge portion of the printed circuit board, parts of the printed lines are formed into elongated terminals which are arranged side by side on both sides of the edge portion. A conventional card edge connector of this type is as shown in FIGS. 1 and 2.
Terminals (not shown) are formed on both sides of an end portion 1 of a printed circuit board. On the other hand, the card edge connector 2 has a box-shaped housing 3 having a slit-shaped inserting hole 4 into which the connecting end portion 1 is inserted. The housing 3 holds metal terminals 5 in such a manner that the metal terminals define a narrow space which is extended from the inserting hole 4 to the back. Each of the terminals 5 has a tongue-shaped abutting part 6 which is flexible and protruded towards the narrow space.
The card edge connector 2 is engaged with the connecting end portion 1 of the printed circuit board as follows: First, the edge of the connecting end portion 1 is set in the inserting hole 4 of the housing 3, and then the connecting end portion 1 is pushed into the inserting hole 4. In this operation, the connecting end portion 1 is moved towards the back while pushing the tongue-shaped abutting parts 6 away from each other which are protruded into the space from both sides which is located behind the inserting hole 4.
When the connecting end portion 1 is inserted into the card edge connector, it is obliquely abutted against the abutting parts 6, so that it deflects the abutting parts 6 while sliding on the latter 6. However, when the abutting parts 6 are pushed away from each other by the connecting end portion 1, the resistance against the pushing operation is relatively large. Hence, the connecting end portion 1 does not smoothly slide on the abutting parts 6 depending on the way of insertion, and at worst the abutting parts 6 may be deformed. Furthermore, since the resistance is great, the engagement of the card edge connector is low in work efficiency.
Furthermore, the connecting end portion la of the printed circuit board, which has been protruded through the engaging surface 14 of the board holder 10, is liable to vertically deflect as indicated by the two-dot chain lines in FIG. 3, depending on how the printed circuit board 12 has been fixed to the board holder 10. This difficulty is due to the fact that, when the printed circuit board is secured to the board holder with a plurality of screws as shown in FIG. xx, the screws are not uniform in vertical position, or tightened with different forces, or the printed circuit board itself is curved. If the connecting end portion la of the printed circuit board is deflected vertically as was described above, then the following difficulties are involved: The card edge connector 2 cannot be engaged with the connecting end portion la of the printed circuit board without twisting it; that is, it is difficult to smoothly engage the former with the latter; in other words, the engagement of the card edge connector with the printed circuit board is low in work efficiency. Furthermore, the twisting of the connecting end portion may deform or damage the abutting parts 6. That is, the engagement of the card edge connector with the printed circuit board is low in reliability.